Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
ban hanh » ban hang
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
y tang » ky tang, 6 tang, 7 tang
ve dao » de dao, ve bao, te dao
di cua » dai cua, doi cua, de cua
va dao » ca dao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach y tang ma hoa. hieu ((ve dao) OR (va dao)) duc ((ban hanh) or (gia thanh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach y tang ma hoa. hieu ((ve dao) OR (va dao)) duc ((ban hanh) OR (gia thanh)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach y tang ma hoa. hieu ((ve dao) OR (va dao)) duc ((ban hanh) or (gia thanh)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach y tang ma hoa. hieu ((ve dao) OR (va dao)) duc ((ban hanh) or (gia thanh)) di cua tre*.